[PATCH 4.14 029/165] hv_netvsc: change GPAD teardown order on older versions

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>

[ Commit 0ef58b0a05c127762f975c3dfe8b922e4aa87a29 upstream. ]

On older versions of Windows, the host ignores messages after
vmbus channel is closed.

Workaround this by doing what Windows does and send the teardown
before close on older versions of NVSP protocol.

Reported-by: Mohammed Gamal <mgamal@xxxxxxxxxx>
Fixes: 0cf737808ae7 ("hv_netvsc: netvsc_teardown_gpadl() split")
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/hyperv/netvsc.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -570,10 +570,15 @@ void netvsc_device_remove(struct hv_devi
 	 */
 	netdev_dbg(ndev, "net device safe to remove\n");
 
+	/* older versions require that buffer be revoked before close */
+	if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_4)
+		netvsc_teardown_gpadl(device, net_device);
+
 	/* Now, we can close the channel safely */
 	vmbus_close(device->channel);
 
-	netvsc_teardown_gpadl(device, net_device);
+	if (net_device->nvsp_version >= NVSP_PROTOCOL_VERSION_4)
+		netvsc_teardown_gpadl(device, net_device);
 
 	/* Release all resources */
 	free_netvsc_device_rcu(net_device);